Unmanned aerial vehicles (UAVs), remotely piloted or self-piloted aircrafts, have oftentimes been tasked to perform a variety of functions beyond the traditional surveillance and target tracking. The UAVs, although small and light-weight, can carry cameras, sensors, communications equipment, or other payloads. However, in order operate safely in shared airspace, a LAY needs to pilot itself at a safe distance from all kinds of airborne collision hazards, e.g., manned aircraft, other UAVs, birds, and low altitude obstacles.
Conventional automated detection and avoid systems such as Traffic Collision Avoidance System (TCAS) and Automatic Dependent Surveillance-Broadcast (ADS-B) can be impractical for vehicles or UAVs of relatively smaller sizes. In particular, the use of these conventional equipment on-board LAY may incur significant weight and power consumption on the very limited equipment carrying capability of UAVs. Further, the cost of equipment such as TCAS and transponders is high. Also, standard TCAS equipment is unable to interact with non-cooperating flying or still (non-moving) objects that are not equipped with the counterpart equipment. Hence, standard TCAS equipment is not able to guide UAVs out of collision under such circumstances.
Thus, there is a need of an on-board collision detection and avoidance system that is compact, light-weight and yet economical for UAVs to automatically detect and avoid air traffic collisions.